Filters: Tags: Raman spectroscopy (X)
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Solid organic matter (OM) in sedimentary rocks produces petroleum and solid bitumen when it undergoes thermal maturation. The solid OM is a 'geomacromolecule', usually representing a mixture of various organisms with distinct biogenic origins, and can have high heterogeneity in composition. Programmed pyrolysis is a common conventional method to reveal bulk geochemical characteristics of the dominant OM while detailed organic petrography is required to reveal information about the biogenic origin of contributing macerals. Despite advantages of programmed pyrolysis, it cannot provide information about the heterogeneity of chemical compositions present in the individual OM types. Therefore, other analytical techniques...
A suite of slate samples collected along a 2 km transect crossing the Lishan Fault in central Taiwan were evaluated to assess the role of ductile strain energy in natural graphitization at greenschist facies metamorphic conditions. Scanning electron microscope (SEM) imaging documents phyllosilicate and quartz replacement textures consistent cleavage development via dissolution-precipitation processes that increase in intensity from east to west. X-ray diffraction data reveal an east-to-west linear decrease in the full-width-at-half-maximum (FWHM) values of the 004 muscovite peaks and shifts towards higher 2θ (lower d) values. Rietveld refinements required two distinct muscovite populations and muscovite microstrain...
These datasets are from an incubation experiment with a combination of two minerals (feldspar or amorphous aluminum hydroxide), one living species of bacteria (Escherichia coli), and one added form of C (Arthrobacter crystallopoietes necromass). We characterized the sorptive properties of the minerals with batch sorption experiments using four low molecular weight C substrates (glucose, oxalic acid, glutamic acid, p-hydroxybenzoic acid): this data is provided in the SterileSorptionData file. We then conducted a 3-wk long incubation in serum vials or imaging chambers. In both incubations, feldspar (200 mg) or amorphous aluminum hydroxide (100 mg) was given 1 of 4 different treatments: (1) a water control with autoclaved...
Categories: Data;
Tags: Mineralogy,
Raman spectroscopy,
Soil Sciences,
USGS Science Data Catalog (SDC),
biota,
Here the spatial variation in Raman estimates of thermal maturity within individual organic domains from several shale geologic reference materials originating from the Boquillas, Marcellus, Niobrara, and Woodford Formations are assessed from the respective Raman response. We show that for all four shales the thermal maturity parameters extracted from Raman spectra by iterative peak fitting can vary widely across distances of ≤5 µm within the same organic domain.
Categories: Data;
Tags: CEMEX quarry,
Carter County, Oklahoma,
Del Rio, Val Verde County, Texas,
Energy Resources,
Geochemistry,
The most commonly used parameter for thermal maturity calibration in basin modelling is mean random vitrinite reflectance (Ro). However, Ro suppression, or lower than expected Ro, has been noted in samples containing a high proportion of liptinite macerals. This has been empirically demonstrated using hydrous pyrolysis experiments of artificial source rock containing various proportions of thermally immature Wyodak-Anderson coal and liptinite-rich kerogen from the Parachute Creek Member of the Green River Formation. Analysis of samples pyrolyzed at 330°C for 72 h demonstrates that the Ro values of both vitrinite and solid bitumen are suppressed, where the degree of suppression increases with increasing amounts of...
Categories: Data;
Tags: Colorado,
Colorado River,
Energy Resources,
Geochemistry,
Hydrous pyrolysis,
This data release contains macro and microscale datasets describing the abundance, valence states, and mineral residence(s) of chromium, iron, and manganese in natural and synthetic mineral mixtures used in laboratory experiments designed to simulate dynamic conditions in an engineered aquifer system [see Izbicki and Groover (2018) and Miller and others (2020)]. The landing page contains primary metadata about this release and an overview "sample information" table containing descriptions of samples, their analyses, and their methods of preparation and preservation. As there is not a one-to-one correlation between samples and types of analyses performed, the overview table is an important navigation tool to locate...
Raman spectroscopy was studied as a thermal maturity probe in a series of Upper Devonian Ohio Shale samples from the Appalachian Basin spanning from immature to dry gas conditions. Raman spectroscopy also was applied to samples spanning a similar thermal range created from 72-hour hydrous pyrolysis (HP) experiments of the Ohio Shale at temperatures from 300 to 360°C and isothermal HP experiments lasting up to 100 days of similar Devonian-Mississippian New Albany Shale. Raman spectra were treated by an automated evaluation software based on iterative and simultaneous modeling of signal and baseline functions to decrease subjectivity. Spectra show robust correlation to measured solid bitumen reflectance (BRo) values...
The molecular composition of petroliferous organic matter and its composition evolution throughout thermal advance are key to understanding and insight into petroleum generation. This information is critical for comprehending hydrocarbon resources in unconventional reservoirs, as source rock organic matter is highly dispersed, in contact with the surrounding mineral matrix, and may be present as multiple organic matter types. Here, a combination of Raman spectroscopy and optical microscopy approaches was applied to a marginally mature (vitrinite reflectance ~0.5%) sample of the Late Cretaceous Boquillas Shale before and after hydrous pyrolysis (HP) at 300 °C and 330 °C for 72 hours. This experimental design allowed...
Categories: Data;
Tags: Energy Resources,
Energy resources,
Hydrous pyrolysis,
Mudrock,
Organic matter,
To refine the use of graptolite and solid bitumen properties as thermal proxies at overmature conditions, we evaluated their evolution via Raman and infrared spectroscopies, reflectance, and geochemical screening in high-temperature hydrous and anhydrous experiments in comparison to naturally matured samples. Naturally matured samples included four overmature Wufeng-Longmaxi marine shales from the Sichuan Basin, China, with solid bitumen reflectance (BRo) values of 2.5-3.6% and graptolite reflectance (GRo) values of 2.3-3.9%. Immature starting materials for pyrolysis experiments included Mesoproterozoic (Ectasian) Xiamaling marine shale from Hebei, China (0.34% BRo, graptolite absent) and graptolite-bearing Ordovician...
Note: this data release is currently being revised and is temporarily unavailable. A suite of slate samples collected along a 2 km transect crossing the Lishan Fault in central Taiwan were evaluated to assess the role of ductile strain energy in natural graphitization at greenschist facies metamorphic conditions. Scanning electron microscope (SEM) imaging documents phyllosilicate and quartz replacement textures consistent cleavage development via dissolution-precipitation processes that increase in intensity from east to west. X-ray diffraction data reveal an east-to-west linear decrease in the full-width-at-half-maximum (FWHM) values of the 004 muscovite peaks and shifts towards higher 2θ (lower d) values. Rietveld...
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